The application of cationic fixing agents to cotton dyed with direct dyes under different pH conditions

The effect of application pH on the effectiveness of the conventional cationic fixing agents Matexil FC-ER and Fixogene CXF in improving the wash fastness of the commercial direct dyes CI Direct Red 89, CI Direct Yellow 106 and CI Direct Blue 85 on cotton has been investigated. While the recommended neutral pH application resulted in improved fastness of the dyeings to the ISOC06/C2 wash fastness test, wash fastness was noticeably better when the fixing agents were applied under alkaline conditions.     

Developments in the soluble lead-acid flow battery

The history of soluble lead flow batteries is concisely reviewed and recent developments are highlighted. The development of a practical, undivided cell is considered. An in-house, monopolar unit cell (geometrical electrode area 100 cm²) and an FM01-LC bipolar (2 × 64 cm²) flow cell are used. Porous, three-dimensional, reticulated vitreous carbon (RVC) and planar, carbon-HDPE composite electrodes have been used in laboratory flow cells. The performance of such cells under constant current density (10–160 mA cm⁻²) cycling is examined using a controlled flow rate (mean linear flow velocity <14 cm s^-1) at a temperature of approximately 298 K. Voltage versus time and voltage versus current density relationships are considered. High charge (<90%), voltage (<80%) and energy (<70%) efficiencies are possible. Possible failure modes encountered during early scale-up from a small, laboratory flow cell to larger, pilot-scale cells are discussed.     

Dehydroisomerization of n-Pentane to Isopentene on Molecular Sieves Impregnated with Platinum

The direct conversion of n-pentane to isopentene by dehydrogenation and isomerization in a single step was studied on Pt supported over SAPO-11, ferrierite (FER) and HZSM5 molecular sieves. The Pt/SAPO-11 presented the best selectivity to mono-branched pentenes. The characterization of acidic sites with isomers of propylamine revealed a better capacity for SAPO-11 to diffuse mono-branched amines and that is considered a consequence of its pore geometry, which could explain the obtained selectivity.     

Manipulating transmit and receive sensitivities of radiofrequency surface coils using shielded and unshielded high-permittivity materials

Objective

To use high-permittivity materials (HPM) positioned near radiofrequency (RF) surface coils to manipulate transmit/receive field patterns.

Materials and methods

A large HPM pad was placed below the RF coil to extend the field of view (FOV). The resulting signal-to-noise ratio (SNR) was compared with that of other coil configurations covering the same FOV in simulations and experiments at 7 T. Transmit/receive efficiency was evaluated when HPM discs with or without a partial shield were positioned at a distance from the coil. Finally, we evaluated the increase in transmit homogeneity for a four-channel array with HPM discs interposed between adjacent coil elements.

Results

Various configurations of HPM increased SNR, transmit/receive efficiency, excitation/reception sensitivity overlap, and FOV when positioned near a surface coil. For a four-channel array driven in quadrature, shielded HPM discs enhanced the field below the discs as well as at the center of the sample as compared with other configurations with or without unshielded HPM discs.

Conclusion

Strategically positioning HPM at a distance from a surface coil or array can increase the overlap between excitation/reception sensitivities, and extend the FOV of a single coil for reduction of the number of channels in an array while minimally affecting the SNR.

     

Quantitative analysis and characterization of the products of the model reaction of n-butyllithium with excess 1,1-diphenylethylene: 1,1-Diphenylhexane and 1,1,3,3-tetraphenyloctane

The model reaction of n-butyllithium with excess (11 M equivalents) 1,1-diphenylethylene (DPE) was reinvestigated using modern characterization techniques including SEC, one dimensional and two dimensional nuclear magnetic resonance (1D and 2D NMR) spectroscopy and electrospray ionization mass spectrometry (ESI MS). The products were the monoadduct, 1,1-diphenylhexane (nBuDPEH), and the diadduct, 1,1,3,3-tetraphenyloctane [nBu(DPE)₂H], formed in 62 mol% and 38 mol% yields, respectively, as determined by SEC and ¹H NMR spectroscopy. The ¹H NMR spectrum of 1,1,3,3-tetraphenyloctane exhibited a terminal methine triplet resonance at δ 3.71 ppm that was uniquely coupled to the adjacent methylene doublet resonance at δ 3.09 ppm, located between the two carbons, each bonded to two phenyl groups [–C(C₆H₅)₂-CH₂-CH(C₆H₅)₂. All of the characteristic ¹H and ¹³C NMR resonances for both adducts were assigned using 2D NMR spectroscopic methods. The diadduct, nBu(DPE)₂H, exhibited unique ¹³C NMR resonances at δ 50.79 ppm for the quaternary carbon resonance [CH₂-C(C₆H₅)_2?CH₂], and at δ 43.74 ppm for the methylene group isolated between the two carbons, each bonded to two phenyl groups [–C(C₆H₅)₂-CH₂-CH(C₆H₅)₂].     

Examination of the effects of LiOH, LiCl, and LiNO3 on alkali-silica reaction

Lithium additives have been shown to reduce expansion associated with alkali-silica reaction (ASR), but the mechanism(s) by which they act have not been understood. The aim of this research is to assess the effectiveness of three lithium additives—LiOH, LiCl, and LiNO₃—at various dosages, with a broader goal of improving the understanding of the means by which lithium acts. The effect of lithium additives on ASR was assessed using mortar bar expansion testing and quantitative elemental analysis to measure changes in concentrations of solution phase species (Si, Na, Ca, and Li) in filtrates obtained at different times from slurries of silica gel and alkali solution. Results from mortar bar tests indicate that each of the lithium additives tested was effective in reducing expansion below an acceptable limit of 0.05% at 56 days. However, different lithium additive threshold dosages ([Li₂O]/[Na₂O_e]) were required to accomplish this reduction in expansion; these were found to be approximately 0.6 for LiOH, 0.8 for LiNO₃, and 0.9 for LiCl. Quantitative elemental analysis indicated that sodium and lithium were both bound in reaction products formed within the silica gel slurry. It is also believed that lithium may have been preferentially bound over sodium in at least one of the reaction products because a greater percent decrease in dissolved lithium than dissolved sodium was observed within the first 24 h. It appears that lithium additives either decreased silica dissolution, or promoted precipitation of silica-rich products (some of which may be nonexpansive), because the dissolved silica concentration decreased with increasing dosage of lithium nitrate or lithium chloride additive.     

Cuticular Hydrocarbons of Termites of the British Virgin Islands

A survey of the termites (Isoptera) of 17 islands of the British Virgin Island (BVI) complex yielded eight taxa belonging to three families. The Kalotermitidae include Neotermes mona (Banks), Cryptotermes brevis (Walker), Procryptotermes corniceps (Snyder), and an undetermined species of Incisitermes, likely Incisitermes nr snyderi (Light) or I. incisus (Silvestri). The only rhinotermitid collected is an undetermined species of Heterotermes (Froggatt). Parvitermes wolcotti (Snyder), Nasutitermes costalis (Holmgren), and N. acajutlae (Holmgren) comprise the Termitidae. Cuticular hydrocarbon mixtures were characterized for each of the taxa. Blends of abundant hydrocarbons are species-specific and can be used to identify a given taxon without the diagnostic castes, soldiers, or imagoes, although the species of Incisitermes were not separable on the basis of cuticular hydrocarbons.     

Galectin‐3‐Binding Glycomimetics that Strongly Reduce Bleomycin‐Induced Lung Fibrosis and Modulate Intracellular Glycan Recognition

Discovery of glycan‐competitive galectin‐3‐binding compounds that attenuate lung fibrosis in a murine model and that block intracellular galectin‐3 accumulation at damaged vesicles, hence revealing galectin‐3–glycan interactions involved in fibrosis progression and in intracellular galectin‐3 activities, is reported. 3,3′‐Bis‐(4‐aryltriazol‐1‐yl)thiodigalactosides were synthesized and evaluated as antagonists of galectin‐1, ‐2, ‐3, and ‐4 N‐terminal, ‐4 C‐terminal, ‐7 and ‐8 N‐terminal, ‐9 N‐terminal, and ‐9 C‐terminal domains. Compounds displaying low‐nanomolar affinities for galectins‐1 and ‐3 were identified in a competitive fluorescence anisotropy assay. X‐ray structural analysis of selected compounds in complex with galectin‐3, together with galectin‐3 mutant binding experiments, revealed that both the aryltriazolyl moieties and fluoro substituents on the compounds are involved in key interactions responsible for exceptional affinities towards galectin‐3. The most potent galectin‐3 antagonist was demonstrated to act in an assay monitoring galectin‐3 accumulation upon amitriptyline‐induced vesicle damage, visualizing a biochemically/medically relevant intracellular lectin–carbohydrate binding event and that it can be blocked by a small molecule. The same antagonist administered intratracheally attenuated bleomycin‐induced pulmonary fibrosis in a mouse model with a dose/response profile comparing favorably with that of oral administration of the marketed antifibrotic compound pirfenidone.     

Workstation variables and visual discomfort associated with VDTs

We have investigated the effects of a range of workstation factors upon the visual symptoms experienced by a group of 92 visual display terminal (VDT) users. Subjects in the study kept a diary over five consecutive working days in which they recorded the types of visual and postural symptoms which occurred and the types of work tasks being performed. Each subject's workstation was analysed for screen legibility and stability, discomfort and disability glare, and required head postures. By the use of multiple regression analysis techniques we have considered the relative contribution of these factors to the symptoms reported by the users of these workstations. Screen legibility significantly influenced the occurrence of symptoms of ocular discomfort and vertical head movements significantly affected the incidence of postural/headache symptoms.